Many hand held or hand guided tools transmit vibration to the hands and arms of the operator. It is known that such transmitted vibration, which is often termed Hand Arm Vibration (HAV), can cause painful and disabling diseases, such as white finger, following regular long term exposure.
Apparatus for monitoring exposure to HAV inducing tools is known. GB 2411472A describes a vibration monitor that is worn by the operator. The vibration monitor of GB 2411472A comprises a vibration sensor and memory. The vibration sensor measures the magnitude and frequency of vibration of a tool being used by the operator, the magnitude and frequency of vibration being stored in the memory along with a time and date stamp. GB 2413189A describes a vibration monitor that is held by an operator. The vibration monitor comprises a vibration sensor and processing electronics. The vibration sensor measures the vibration of a tool being used by the operator and the processing electronics determines the operator's cumulative exposure to the vibration and provides an indication to the operator before exposure to the vibration exceeds a safe level. GB 2299168A describes a vibration monitor that is worn on the wrist of an operator. The vibration monitor comprises a vibration sensor and processing electronics. The vibration sensor measures vibrations experienced by the operator during use of a tool and the processing electronics operates an alarm when an accumulated time that the vibration level exceeds a predetermined threshold exceeds a predetermined duration.
The present inventor has appreciated that the above described apparatus have disadvantages.
It is therefore an object of the present invention to provide apparatus for measuring vibration of a hand held tool.
It is a further object of the present invention to provide apparatus for measuring a duration of vibration of a hand held tool.